Following JP for a while now and he preaches upper/lower(maybe not for the REALLY TOP open strong AF guys). His thought proces is you hit everything at least twice a week(Upper, lower rest repeat for example). That means you stimulate a muscle 2/3 times per week instead of just 1(brosplit for example).
For the really big strong open bodybuilders this maybe would dig an recovery hole(even though JP does upper/lower from time to time, and he says he literally sees double the growth from it when he does and can handle it). Of course AAS/GH and stuff does something for protein synthesis, but it also let´s you recover more quick. It seems to be normal/the trend to do brosplits(or PPL) those days because (most) of the really TOP dogs do it, but should we?
*And of course you should train the way you enjoy it yadayada but just some food for thought.
What I liked more was the PPL when I started low volume training (top set, back off,5-8 exercises per workout):
Push
Pull
Rest
Legs
Rest
It was very effective, but after a while had to deload too often for my taste, because my CNS was never fresh enough.
Now I use this split only when cutting since progressive overload doesn't happen that much on low calories.
Then I tried sort of bro split, and i prefer this.
Back + 1 movement for back delts
Shoulders and Bis
Quad dominant day + 1 movement for back delts
Rest
Chest and Tris
Ham dominant day + 1 movement for back delts
Rest
My CNS rests more and I can keep progressing with weights/reps.
This thing about hitting a muscle twice a week doesn't work that good for me. Well it works only for back delts tbh.
When I am starting stalling with progress, I just take a week off the gym and eat half the carbs, keep the cardio, take 500 metformin daily to restore some insulin sensitivity and that's it.